Turbine cylinder



Jan. 5, 1932. F. HODGKINSON imlmlmm INVENTOR F- HoclQKi nson WITNESS (5. 13

ATTORNEY Patented Jan. 5, 1932 UNITED STATES PATENT'OFFICE FRANCIS HOZDG-KIN'SON, OF 'SWARTHMORE, PENNSYLVANIA, ASSIGNOR TO WESTING- 7 HOUSE: ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OFPENNSYL- 1 VANIA TURBINE CYLINDER Original application filed May 22, 1925, Serial No. 32,150. Divided and this application filed May 29, 1928.

' Seria1 No.281,526. l

This application is a division of application, Serial No. 32,150, filed May 22, 1925 (since issued as Patent No.f1,682,338, August 28, 1928) r Y My invention relates to elastic fluid turbines, more particularly to turbines employing relatively higher pressures than have hithertobeen commonly used, and it has for its object the provision of apparatus ofthe character designated which shall be sturdy of :design and el'ficient in operation;

A specific object-is to provide a casing of greater strength than has heretofore been employed, and to bolt thcparts of {said casing firmly together. I i A further object is to provide .means whereby a definite stress may be imposed on each bolt. 7 i

Apparatus embodying features of my invention is illustrated in theaccompanying drawings forminga'part of'this specification inv which:

Fig. 1 is a view-in elevation showing a turbine made in accordance with my invention;

F ig. 2 is a longitudinal, vertical section of Fig 1; I

Figs. 8' and 4 are transversesectional views taken through the turbine casing along the lines IIIIII and IV'IV respectively of Fig: '1, said sections being at the exhaust outlet and motive fluid inlet respectively, but offset at the sides toshow the bolt holes and the boltsin the casing; and,

Fig. 5 is a sectional view'of a bolt employed in holding parts of the turbine cylinder together and including a heating element employed in accordance with myinvention.

' In the design of elastic fluid turbines employing relatively high initial pressures, for example, upwards of 1000 lbs. per square inch, diihculties have been encountered in providing a. casing capableof withstanding the high pressure therein without distortion in operation.

In accordancewith my invention, I form the turbine casingior cylinder from'twoparts of suitable: material, preferably two blocks of forged steel of approximately rectangular form. In order to securethe two halves to gether, 'I providebolts, which may extend the depth of the blocks, and I provide a hole from end-to-end in each of the bolts whereby they may be heated and tightened to prov1de a definite stretch of the bolts upon re turning approximately to the temperature of the casing. 'At the exhaust end of the casing a deflector element is provided, and securing means therefor are arranged which also serve-the purpose of staying the exhaust end of the turbine.

Referring now to thedrawings for a more detailed description of my invention, I show,

with motive fluid inlets 1'111andwith an exhaust outlet 12. Referring to Figs. 2 t0 4, inclusive, the turbine 10 embodies acasing or cylinder. 14 which is formed from twoblocksof forged steel of approximatelv rec tangular .form, the blocks being bored out to form the cylinder as shown in Figs. 3 and 4. At 15, is shown a rotor which is provided with a plurality of rows of moving blades 1616, for cooperation with alternate rows of stationary blades 1717 carried bv the cylinder 14. In order. to holdthe staticnarv blades 17 in place, I provide grooves 1818 bored out of'thesolid metal, into which the blade roots 'are'inserted and wedged in place inany manner known to the art. At 18. I show a nozzle chamber in the form of a circulargroove machined in the casing 14 and communicating with a nozzle block 20.

While I have-illustrated a turbine having a solid rotor with rows of moving blades interleaving with stationary blades carried by the casing, it is within the purview of my invention to provide a rotor of the multiple disc type and mount diaphragms with nozzle elements in the grooves 1818 in the casing.

The two halves of the casing 14 are held together by means of relatively long bolts 19-19 which may extend the entire depth of the casing 14, said bolts being provided at the top with nuts 2121 and at the bottom with nuts 22-22, the nuts 21 and 22 being screwed down tightly in order to hold the two halves. together and to withstand the high pressure employed in the turbine. As these bolts are'necessarily large, I have found in Fig. 1, my improved turbine provided 7 them diliicult to tighten with assurance of imposing thereupon definite stresses. In order to more firmly secure the halves of the casing together, I provide means for heating the bolts 19 before the nuts 21 and 22 are tightened thereon, and also means for measuring the stretch of the bolts in order that a definite and uniform stress may be placed thereon. To this end, each bolt is provided with a hole 23 extending longitudinally therethrough, preferably centrally of the bolt and from end to end, and with plane surfaces accurately machined on the ends thereof.

Each bolt is tightened and'the stretch thereofdetermined in the following manner: Micrometer measurements of the length of the bolt are made by applying a micrometer to the plane surfaces on the ends. Aheating element, for example, an electric heating element 24, is placed withintheihole 23, as shown in Fig. 5, and an electrical current is passed through it until the bolt is sufficiently heated.

One or bothof the nuts 21 and 22 are turned a sufficient amount to provide the desired stretch. The amount that the nuts must be turned can readily be estimated, since the physical characteristics of the bolt material and the pitch of the thread are known.

After the nuts are tightened by being turned the correct amount, the bolt is allowed measured to check the stretch. If it has not been stretched the proper amount to provide the desired stress, the bolt is again heated and one or both of the nuts 21 and 22 turned to correct the amount of stretch. After cooling, the stretch may again be checked.

As noted above, the stress imposed upon the bolts, which is-the force with which the bolts hold the halves of the casing together, is determined from the amount of stretch. H By uniformly stressing the bolts, the casing parts are evenly securedtogether and the possibility of leakage minimized.

At the exhaust endof the turbine, I pro vide a deflector element 25 in the form of a ring surrounding the rotor 15 and resting in appropriate grooves formed in the exhaust end of the casing 14. In order to hold the deflector ring in position and to stay the exhaust chamber against the relatively high exhaust pressure, I provide bolts 25-25',a suitable number of which extend longitudinally of the turbine cylinder through the exhaust chamber and the deflector ring 25 as shown. At 26, Fig. 2, I show a dummy piston formed on the rotor 15 andhaving labyrinth packing elements 27 cooperating with similar elements carried by the casing 14 in order to prevent leakage thereby. Such leakage as does occur past the dummy piston 26 may be carried out through a conduit 28.

To prevent anunsafe pressure within the While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is: r

1. In a turbine, a casing formed from blocks of forged steel, a motive fluid inlet in thecasing, an exhaust outlet for the casing, a deflector forthe exhaust outlet and disposed within ,the casing on the discharge side of the last'blade row, and securing means adaptedto hold the deflector in place and stay the exhaust outlet.

2. In a turbine, a casing formed from blocks of forged steel, a motive fluid inlet in the casing, an exhaust outlet at one end of the casing, a deflector for the exhaust outlet and disposed within thecasing on the dis- 3. In a turbine, a casing formed from blocks of forged steel, a motive fluid inlet in the casing, an exhaust outlet at one end of the casing, a diffuser comprising a deflecting ring surrounding the rotor and supported within the casing opposite the exhaust outlet, and bolts extending longitudinally of the Gas ing through the diffuser for holding it in place and staying the exhaust outlet.

l. An elastic fluid turbine having a cas ing formed in two parts from blocks of steel, and bolts for holding the parts of the casing together, said bolts having hollow interiors extending for the major portion of the length thereof for the insertion of heating means.

5. An elastic fluid turbine having a casing formed in two partsfrom blocks of forged steel, said casing having interior grooves formed in the solid metal for the insertion of turbine elements, and bolts extending the depth of the casing for holding the parts together, said bolts having hollow interiors extending for the major portion of the length thereof.

' .6. An elastic flui-dturbine having a casing a as formed in two parts from blocks of steel, said casing having interior grooves formed in the solid metal for the insertion of stationary turbine elements, and hollow bolts extending through the casing the entire depth thereof for holding the parts together, the hollow interiors of the bolts being adapted for the reception of heating means.

In testimony whereof I have hereunto subscribed my name this fourth day of May,

FRANCIS I-IODGKINSON. 

